Effect of Liquid Media and in Vitro Pre-acclimatization Stage on Shoot Elongation and Acclimatization of Date Palm (Phoenix dactylifera L.) cv. Najda

The effect of stationary liquid media to improve shoots elongation indate palm cv. najda and an in vitro pre-acclimatization stage to increase thesurvival percentage of plantlets in the greenhouse was investigated. two basalliquid media were tested: full strength and half strength murashige and skoogmedium (ms). media were devoid of plant growth regulators (pgrs), containing0.5 mg/l 6-benzylaminopurine (bap) or 0.5 mg/l indole-3-butyric acid (iba)and 0.5 mg/l bap. after three months of culture, all liquid media wereefficient and allowed to overcome slow growth problem. the maximum shootelongation was 11.3 cm, obtained in ms supplemented with 0.5 mg/l bapand 0.5 mg/l iba. the shoots were isolated and transferred either to thegreenhouse or to one month in vitro pre-acclimatization stage in a pgrs-freesolid medium (ms or ms/2) then to the greenhouse. a higher surviving rate(ranging from 70 to 86 %) was obtained after one month pre-acclimatizationcompared with the direct transfer to the greenhouse (12–28 %).